The present invention relates to aircraft and to methods of manufacturing an aircraft comprising a foldable aerodynamic structure.
There is a trend towards increasingly large passenger aircraft with higher performance efficiency (for example fuel burn reduction), for which it is desirable to have correspondingly large wing spans. However, the maximum aircraft span is effectively limited by airport operating rules which govern various clearances required when manoeuvring around the airport (such as the span and/or ground clearance required for gate entry and safe taxiway usage).
In some suggested designs, aircraft are provided with wings which may be rotated about an axis that is orientated at a compound angle, such that part of the wing is folded (for example upwardly, or downwardly, and rearwardly or forwardly), to reduce the span of the aircraft on the ground (compared to when the aircraft is configured for flight). However, a disadvantage with such arrangements (an example of which is the folding wing on the Grumman Avenger aircraft) is that they tend to require a series of secondary structures to be moved to avoid clashing between the inner and outer parts of the wing. Another disadvantage in folding wing designs more generally, is that the wing tends to have limited volume in the vicinity of the junction between the fixed and folded parts of the wing. In order to accommodate essential internal structure (e.g. ribs, spars or other support structure), and/or aircraft systems (e.g. actuators) within the wing, it may be necessary to redesign the internal layout of the wing, locally increase the wing volume in the vicinity of the junction, and/or significantly constrain the possible location of that junction.
The present invention seeks to mitigate at least some of the above-mentioned problems.